Physics Ch 8

Question 1

Linear momentum

Answer 1

product of a system’s mass multiplied by its velocity (p = mv); SI unit = kg m/s

Question 2

Newton’s Second Law of Motion

Answer 2

net external force equals the change in momentum of a system divided by the time over which it changes

Question 3

Change in momentum

Answer 3

delta p = Fnet times the change in time; equals the average net external force multiplied by the time this force acts

Question 4

Conservation of momentum principle

Answer 4

total momentum is conserved for any isolated system

Question 5

Isolated system

Answer 5

system for which the net external force is zero

Question 6

Quarks

Answer 6

fundamental constituent of matter and an elementary particle

Question 7

Elastic collision

Answer 7

collision that conserves internal kinetic energy; can only be achieved with subatomic particles

Question 8

Internal kinetic energy

Answer 8

sum of the kinetic energies of the objects in the system

Question 9

Inelastic collision

Answer 9

collision in which the internal kinetic energy changes (it is not conserved); forces between colliding objects may remove or add internal kinetic energy

Question 10

Perfectly inelastic collision

Answer 10

a collision in which the objects stick together is sometimes called this because it reduces internal kinetic energy more than does any other type of inelastic collision; reduces internal kinetic energy to the minimum it can have while still conserving momentum

Question 11

Point masses

Answer 11

structureless particles that cannot rotate or spin